Process for the manufacture of 6-bromo-2-hydroxy-naphthalene and its substitution products



Patented Dec. 13, 1932 UNITED STATES JOHANNES WOLLEMANN, OF OFFENBACI-I-ON-THE-MAIN, GERMANY, ASSIGNOR TO GEN-v ERAL ANILINE WORKS, INC., OF-NEW YORK, N. Y., A CORPORATION OF DELA- WARE PROCESS FOR THE MANUFACTURED]? 6-IBROMO-2-HYDROXY-NAIPI-ITHALENE AND ITS f r SUIBSTITU'TIOI'I PRODUCTS No Drawing. Application fi led October 26, 1931, Serial No. 571,276, and in Germany November 1,1930.

My present invention relates to an improved process for the manufacture of 6- bromo-2-hydroxy-naphthalene and its substitution products.

In German Specification No. 396,519 is described the manufacture of 6-halogen-2-hydroxy-3-naphthoic acid by treating 1.6-dihalogen-2-hydroxy-3-naphthoic acid with a tin salt in alcoholic solution, that is to say in a manner analogous to the manufacture of 6-bromo-2-naphthol described by Franzen and Stituble (J ourn. fur prakt. Ohemie, new edition, volume 103, page 369).

My present process, which avoids the use of the expensive tin compounds, comprises heating a hydroxynaphthalene compound of the general formula: 1

Br X

wherein X means hydrogen or a carboxylic acid group, Y means hydrogen or bromine I and at least one of X and Y is hydrogen.

In order to further illustrate my invention the following examples are given, the parts being by weight and all temperatures in centigrade degrees. But I wish 1t to be understood that my invention is not limited to the particular conditions or specific products mentioned therein.

-washed and dried. It melts at'262 and corf responds tothe formula: X

.whole is boiled under a reflux condenser for 36 hours, while gradually, that is after 12 ,24=

'kali. metal salt of l.6dibromo-2-hydrox;y- 'naphthaleneecarboxylic acid. 4

PATENT oFFlcE Ereample 1 100 parts of 1.6-dibromo-2-hydroxy-naphe thalene-3-carboxylic acid are made to a paste by means of 1500 parts of hot water and converted into the monosodium salt by the ad- Q dition of parts of'calcined soda. After the evolution of carbon dioxide 100 parts of crystallized neutral sodium sulfite and parts of soda-(calcined) are added and the whole is heated in an autoclave for 8 hours to 150. When the reaction liquid is cold, the formed precipitate is filtered, dissolved in 3000 parts of boiling water and acidified by parts of'20", Bl hydrochloric acid. 5 The free G-bromo-2-hydroxy-naphthalene-3-' carboxylic acid thus 0 formed isffiltered,

Example 2 ,75 A solution of 68.8 parts of 1.6-dibromo-2- hydroXy-naphthalene-3ecarboxylic acid in 20 parts of calcined soda and 6000 parts of'water is mixed with a solution of 60 parts of crystallized neutral sodium sulfite. Then the and 30 hours, again 10 parts each of crystallized sodium sulfite are added. The formed 6-bromo-2-hydroxy-naphthalene 3 carboxyas lic acid is precipitated with hydrochloric acid, filtered, washed with water and dried. It is identical to the compound of Example 1. The reaction may belikewise carried 0 t .by means of potassium sulfite and a mono 1-; a0

Example 3 A mixture of 363 parts of 1.6dibromo-2-.? hydroXy-naphthalene, 1200 parts of alcohol, 624 parts of a potassium sulfite solution corresponding to 2 72parts of K SO and 600 parts of water is boiled under a reflux con denser for 12 hours. The alcohol is distilledee A mixture of 190.5 parts of 1.4.6-tribromo- Q-hydrOXy-naphthalene, 800 parts of alcohol, 260 parts of 43.6% potassium sulfite solution and 250 parts of water is boiled under a reflux condenser for 12 hours. Then the alcohol is distilled off and the residue is diluted with 750 parts of hot water. The mass is 4. Process which comprises heating 1.4.6- tribromo-2-hydroxynaphthalene of the following formula with an alkali metal sulfite.

In testimony whereof, I aflix my signature.

J OHANNES WOLLEMANN stirred until cool, the precipitated product is filtered, washed with water and dried. The 4.6-dibromo-2-hydroxy-napl1thalene thus obtained melts at 134 and corresponds to the formula:

I claim: 1 a 1. Process which comprises heating a hydroxynaphthalenecompound of the general formula:

wherein X means hydrogen or the group COO-alkali metal, Y means hydrogen or bromine and at least one of X and Y is hydrogen, with an alkali metal sulfite.

2. Process which comprises heating 1.6- dibromo-2-hydr0xy naphthalene of the formula: I

with an alkali metal sulfite.

3. Process which comprises heating an alkali meta-lsalt of 1.6-dibr0mo-2-hydroxynaphthalene-3-carboxylic acid of the formula:

B COO-alkali metal with an alkali metal sulfite.

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